Hi Alex,
this should be the new standard (promoted by facebook) to let links shared on facebook to open in the mobile application (if you have one).
So when you configure your FB app and you set your iOS and adroid app ID in the settings, then whenever a user opens a link on facebook from their mobile if he has your application, the link opens that content inside your native app, otherwise it opens the standard html version of the link.
It is really a nice feature. not urgent but you should put it in your todolist. another good reason to renew your Subscription next year!

or you could make a new type of Subscription for it
Here you can see the diagram:
developers.facebook.com/docs/applinks/overview
Here you find the documentation:
applinks.org/documentation/